Some basic questions about registration-table (Winbox)

Hello everyone,

I am new using RouterOs and Wnbox and I want to know the meaning of some of the parameters that are shown in the wireless registration-table in Winbox when a device is connected by Wi-Fi.
I have read the Mikrotik Wiki but they don´t explain well these concepts and I need an explanation of them. These concepts are:

Last Activity
Tx/Rx Strength
Tx Rate
Rx Rate

Thank you!